Abstract: F23.00002 : Weyl and Heusler compounds*

Author:

Claudia Felser(Max Planck Institute Chemical Physics for Solids)

Topological insulators (TIs), Weyl and Dirac semimetals are new quantum
states of matter. Heusler compounds are a remarkable class of materials
which exhibit a wide range of multifunctionalities including tunable
topological insulators [1]. The required band inversion has already been
unambiguously identified by angle-resolved photoemission [2]. Weyl and Dirac
semimetals open up new research directions and applications that result from
the large Berry phases that they exhibit: these lead to giant anomalous Hall
effect (AHE) and spin Hall effects [3]. In the C1b Heusler compounds, the
inclusion of rare earth atoms allows the use of magnetic exchange fields to
induce Weyl points [4] in magnetic fields, which break time-reversal
symmetry. In GdPtBi several signatures of a Weyl semimetal have been
observed, ranging from a large longitudinal negative Magnetoresistance, to
an AHE and a Seebeck effect [4]. Recently Co$_{\mathrm{2}}$TiSn and other
Co$_{\mathrm{2}}$-Heusler compounds were found to be Weyl semimetals [5]:
these materials have an energy-gap for one spin orientation and crossing
points in the other spin direction. The Berry phase induces a giant AHE in
these ferromagnets. However, even antiferromagnetic Heusler compounds can be
designed with large Berry phases as a consequence of Weyl points close to
the Fermi energy [6]: this has recently been proven via a giant AHE for
single crystals of Mn$_{\mathrm{3}}$Sn and Mn$_{\mathrm{3}}$Ge [7].
[1] Chadov, et al., Nat. Mat.. 9,541 (2010), Lin, et al., Nat. Mat. 9, 546
(2010)
[2] Liu, et al., N. Nat. Com. 7 12924 (2016)
[3] Sun, et al., arXiv:1604.07167
[4] Hirschberger et al. Nat. Mat. (2016) Shekhar, et al. arXiv: 1604.01641
[5] Wang et al., arXiv:1603.00479, K\"{u}bler and Felser, EPL 114, 47005
(2016)
[6] K\"{u}bler and Felser, EPL 108 67001 (2014), Zhang, et al.,
arXiv:1610.04034
[7] Nayak, et al., Science Advances 2 e1501870 (2016) , Nakatsuji, Kiyohara
and Higo, Nature 527 212 (2015)

*ERC Idea Heusler

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.MAR.F23.2